JP2021014021A - Liquid jet head and liquid jet system - Google Patents

Abstract

To provide a liquid jet head and a liquid jet system which can more efficiently recover a liquid in the vicinity of a nozzle.SOLUTION: A liquid jet head having a supply port and a discharge port of a liquid includes a pressurization chamber 12 communicating with one of the supply port and the discharge port, a nozzle 21 for discharging the liquid pressurized by the pressurization chamber 12, a first flow channel 201 extending in a first direction+Z between the pressurization chamber 12 and the nozzle 21, and a second flow channel 202 that communicates with the supply port and the other discharge port, is branched from the first flow channel 201 and extends in a second direction-Y crossing the first direction+Z, in which the first flow channel 201 has a downstream side first flow channel 201a close to the nozzle 21 and an upstream side first flow channel 201b closer to the pressurization chamber 12 than the downstream side first flow channel 201a, and a center axis C1 of the downstream side first flow channel 201a is positioned closer to a third direction+Y that is an opposite direction to the second direction than a center axis C2 of the upstream side first flow channel 201b.SELECTED DRAWING: Figure 3

Description

The present invention relates to a liquid injection head and a liquid injection system for injecting a liquid from a nozzle, and particularly to an inkjet recording head and an inkjet recording system for injecting ink as a liquid.

In the liquid injection head that injects a liquid, for example, in order to discharge bubbles contained in the liquid, to suppress thickening of the liquid, and to suppress sedimentation of components contained in the liquid, the liquid injection head A liquid injection system that circulates the liquid inside has been proposed (see, for example, Patent Document 1).

In the liquid injection head of Patent Document 1, the liquid in the liquid injection head is circulated through a branch flow path provided in the vicinity of the nozzle to suppress thickening due to drying of the liquid not injected from the nozzle.

JP-A-2018-103602

However, there is a demand for a liquid injection head that can more efficiently recover the liquid in the vicinity of the nozzle.

It should be noted that such a problem exists not only in the inkjet recording head but also in the liquid injection head that injects a liquid other than ink.

In view of such circumstances, it is an object of the present invention to provide a liquid injection head and a liquid injection system capable of more efficiently recovering the liquid in the vicinity of the nozzle.

An aspect of the present invention for solving the above problems is a liquid injection head having a liquid supply port and a liquid discharge port, the pressure chamber communicating with one of the supply port and the discharge port, and the pressure chamber. Between the nozzle for discharging the pressurized liquid, the first flow path extending in the first direction between the pressurizing chamber and the nozzle, and communicating with the other of the supply port and the discharge port, A second flow path that branches from the first flow path and extends toward a second direction that intersects the first direction is provided, and the first flow path is a downstream first flow path close to the nozzle. And an upstream side first flow path closer to the pressurizing chamber than the downstream side first flow path, and the central axis of the downstream side first flow path is the center of the upstream side first flow path. The liquid injection head is characterized in that it is located closer to the third direction, which is the direction opposite to the second direction, with respect to the shaft.

Another aspect of the liquid injection system includes the above-mentioned liquid injection head and a mechanism for supplying the liquid to the supply port and collecting the liquid from the discharge port to circulate the liquid. is there.

It is a top view of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing explaining the streamline of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing explaining the streamline of the comparative example of the recording head which concerns on Embodiment 1. FIG. It is sectional drawing of the recording head which concerns on Embodiment 2. FIG. It is sectional drawing of the modification of the recording head which concerns on Embodiment 3. FIG. It is a figure which shows the schematic structure of the recording apparatus which concerns on one Embodiment. It is a block diagram explaining the liquid injection system which concerns on one Embodiment.

The present invention will be described in detail below based on the embodiments. However, the following description shows one aspect of the present invention, and can be arbitrarily changed within the scope of the present invention. Those having the same reference numerals in each figure indicate the same members, and the description thereof is omitted as appropriate. Further, in each figure, X, Y, and Z represent three spatial axes that are orthogonal to each other. In the present specification, the directions along these axes are the X direction, the Y direction, and the Z direction. The direction in which the arrow in each figure points is the positive (+) direction, and the opposite direction of the arrow is the negative (-) direction. Further, the Z direction indicates a vertical direction, the + Z direction indicates a vertically downward direction, and the −Z direction indicates a vertically upward direction.

(Embodiment 1)
An inkjet recording head, which is an example of the liquid injection head of the present embodiment, will be described with reference to FIGS. 1 to 6. Note that FIG. 1 is a plan view of an inkjet recording head, which is an example of the liquid injection head according to the first embodiment of the present invention, as viewed from the nozzle surface side. FIG. 2 is a cross-sectional view taken along the line AA'of FIG. FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 is a cross-sectional view illustrating the first flow path and the second flow path. FIG. 5 is a diagram illustrating streamlines in the flow path of FIG. FIG. 6 is a diagram illustrating streamlines in the flow path of the comparative example.

As shown in the figure, the inkjet recording head 1 (hereinafter, also simply referred to as the recording head 1), which is an example of the liquid injection head of the present embodiment, has a flow path forming board 10, a communication board 15, and a nozzle plate 20 as flow path boards. , A plurality of members such as a protective substrate 30, a case member 40, and a compliance substrate 49.

The flow path forming substrate 10 is made of a silicon single crystal substrate, and a diaphragm 50 is formed on one surface thereof. The diaphragm 50 may be a single layer or a laminate selected from a silicon dioxide layer and a zirconium oxide layer.

The flow path forming substrate 10 is provided with a plurality of pressure chambers 12 constituting the individual flow paths 200, which are partitioned by a plurality of partition walls. The plurality of pressure chambers 12 are arranged side by side at a predetermined pitch along the X direction in which a plurality of nozzles 21 for ejecting ink are arranged side by side. Further, in the present embodiment, one row in which the pressure chambers 12 are arranged side by side in the X direction is provided. Further, the flow path forming substrate 10 is arranged so that the in-plane direction includes the X direction and the Y direction. In this embodiment, the portion of the flow path forming substrate 10 between the pressure chambers 12 arranged side by side in the X direction is referred to as a partition wall. This partition wall is formed along the Y direction. That is, the partition wall is a portion of the flow path forming substrate 10 that overlaps the pressure chamber 12 in the Y direction.

In the present embodiment, only the pressure chamber 12 is provided in the flow path forming substrate 10, but the flow path is crossed more than the pressure chamber 12 so as to impart flow path resistance to the ink supplied to the pressure chamber 12. It is also possible to provide a flow path resistance imparting portion having a narrowed cross-sectional area.

A diaphragm 50 is formed on one side of the flow path forming substrate 10 in the −Z direction, and the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are formed on the diaphragm 50. The piezoelectric actuator 300 is formed by laminating by a film forming and lithography method. In the present embodiment, the piezoelectric actuator 300 is an energy generating element that causes a pressure change in the ink in the pressure chamber 12. Here, the piezoelectric actuator 300 is also referred to as a piezoelectric element, and refers to a portion including a first electrode 60, a piezoelectric layer 70, and a second electrode 80. Generally, one electrode of the piezoelectric actuator 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure chamber 12. In the present embodiment, the first electrode 60 is a common electrode of the piezoelectric actuator 300, and the second electrode 80 is an individual electrode of the piezoelectric actuator 300, but there is no problem even if this is reversed due to the convenience of the drive circuit and wiring. In the above-mentioned example, the diaphragm 50 and the first electrode 60 act as the diaphragm, but the present invention is not limited to this. For example, only the first electrode 60 is provided without the diaphragm 50. It may act as a diaphragm. Further, the piezoelectric actuator 300 itself may substantially also serve as a diaphragm.

Further, a lead electrode 90 is connected to each of the second electrodes 80 of each of such piezoelectric actuators 300, and a voltage is selectively applied to each of the piezoelectric actuators 300 via the lead electrode 90. ..

Further, the protective substrate 30 is bonded to the surface of the flow path forming substrate 10 in the −Z direction.

In the region of the protective substrate 30 facing the piezoelectric actuator 300, a piezoelectric actuator holding portion 31 having a space that does not hinder the movement of the piezoelectric actuator 300 is provided. The piezoelectric actuator holding portion 31 may have a space that does not hinder the movement of the piezoelectric actuator 300, and the space may or may not be sealed. Further, the piezoelectric actuator holding portion 31 is formed in a size that integrally covers a row of a plurality of piezoelectric actuators 300 arranged side by side in the X direction. Of course, the piezoelectric actuator holding portion 31 is not particularly limited to this, and may individually cover the piezoelectric actuators 300, and for each group composed of two or more piezoelectric actuators 300 arranged side by side in the X direction. It may be a covering.

As such a protective substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, ceramic material, etc., and in the present embodiment, the same material as the flow path forming substrate 10. It was formed using the silicon single crystal substrate of.

Further, the protective substrate 30 is provided with a through hole 32 that penetrates the protective substrate 30 in the Z direction. The vicinity of the end of the lead electrode 90 drawn out from each piezoelectric actuator 300 is extended so as to be exposed in the through hole 32, and is electrically connected to the flexible cable 120 in the through hole 32. The flexible cable 120 is a flexible wiring board, and in the present embodiment, a drive circuit 121 which is a semiconductor element is mounted. The lead electrode 90 and the drive circuit 121 may be electrically connected without using the flexible cable 120. Further, the protective substrate 30 may be provided with a flow path.

Further, on the protective substrate 30, a case member 40 for defining a supply flow path communicating with the plurality of pressure chambers 12 together with the protective substrate 30 is fixed. The case member 40 is provided by joining the protective substrate 30 on the side opposite to the flow path forming substrate 10 and also joining the communication plate 15 described later.

Such a case member 40 is provided with a first liquid chamber portion 41 forming a part of the first common liquid chamber 101 and a second liquid chamber portion 42 forming a part of the second common liquid chamber 102. Has been done. The first liquid chamber portion 41 and the second liquid chamber portion 42 are provided on both sides of the pressure chamber 12 in a row in the Y direction.

Each of the first liquid chamber portion 41 and the second liquid chamber portion 42 has a concave shape that opens on the −Z side surface of the case member 40, and extends over a plurality of pressure chambers 12 arranged side by side in the X direction. It is provided continuously.

Further, the case member 40 has a supply port 43 that communicates with the first liquid chamber portion 41 to supply ink to the first liquid chamber portion 41 and a second liquid chamber portion 42 that communicates with the second liquid chamber portion 42. A discharge port 44 for discharging ink from the ink is provided.

Further, the case member 40 is provided with a connection port 45 through which the flexible cable 120 is inserted so as to communicate with the through hole 32 of the protective substrate 30.

On the other hand, a communication plate 15, a nozzle plate 20, and a compliance substrate 49 are provided on the + Z side of the flow path forming substrate 10 opposite to the protective substrate 30.

A plurality of nozzles 21 for ejecting ink in the + Z direction are formed on the nozzle plate 20. That is, the nozzle plate 20 of the present embodiment arrives at the nozzle substrate. In the present embodiment, as shown in FIG. 1, a plurality of nozzles 21 are arranged on a straight line along the X direction to form a row of nozzle rows 22. The nozzle 21 refers to a member provided with the first flow path 201, which is formed on the nozzle plate 20 which is a member different from the communication plate 15 in the present embodiment.

The nozzle 21 has a first nozzle 21a and a second nozzle 21b having different inner diameters arranged side by side in the Z direction, which is the plate thickness direction of the nozzle plate 20. The inner diameter of the first nozzle 21a is smaller than that of the second nozzle 21b. The first nozzle 21a is arranged on the outer side of the nozzle plate 20, that is, on the + Z side, and ink is ejected as ink droplets from the first nozzle 21a in the + Z direction. That is, ink droplets are ejected from the nozzle 21 of the present embodiment in the + Z direction, which is the first direction.

Further, the second nozzle 21b is arranged on the −Z side of the nozzle plate 20, and communicates with the + Z side end of the first flow path 201 extending in the + Z direction, which will be described in detail later.

By providing the nozzle 21 with the first nozzle 21a having a relatively small inner diameter in this way, it is possible to improve the flow velocity of the ink and improve the flight speed of the ink droplets ejected from the nozzle 21. Further, by providing the nozzle 21 with a second nozzle 21b having a relatively large inner diameter, the ink in the individual flow path 200 flows from the first common liquid chamber 101 to the second common liquid chamber 102, which will be described in detail later, so-called. When the circulation is performed, the portion of the nozzle 21 that is not affected by the circulation flow can be reduced. That is, it is possible to generate an ink flow in the second nozzle 21b during circulation, increase the velocity gradient in the nozzle 21, and replace the ink in the nozzle 21 with new ink supplied from the upstream. .. However, if the inner diameter of the second nozzle 21b is made too large as compared with the first nozzle 21a, the ratio of inertia between the second nozzle 21b and the first nozzle 21a becomes large, and ink droplets are continuously ejected. The position of the ink meniscus in the nozzle 21 is not stable. That is, when the ratio of inertia between the second nozzle 21b and the first nozzle 21a becomes large, the meniscus of the ink moves into the second nozzle 21b instead of staying in the first nozzle 21a, and stable ink droplet ejection is continuously performed. And you will not be able to do it.

Further, if the inner diameter of the second nozzle 21b is made too small, it becomes difficult for ink to flow into the second nozzle 21b during circulation. Further, if the inner diameter of the second nozzle 21b is made too small, the flow path resistance from the pressure chamber 12 to the nozzle 21 becomes large and the pressure loss becomes large, so that the weight of the ink droplets ejected from the nozzle 21 becomes small. Therefore, the piezoelectric actuator 300 must be driven with a higher drive voltage, and the discharge efficiency is lowered. Therefore, the sizes of the first nozzle 21a and the second nozzle 21b are appropriately determined in consideration of ink replacement performance, ejection stability, ejection efficiency, ink droplet flight speed, and the like during circulation.

The first nozzle 21a and the second nozzle 21b are provided so that the opening shapes are substantially the same in the Z direction. As a result, a step is formed between the first nozzle 21a and the second nozzle 21b. Of course, the shapes of the first nozzle 21a and the second nozzle 21b are not limited to this, and for example, the inner surface of the second nozzle 21b may be an inclined surface inclined with respect to the Z direction. That is, the inner diameter of the second nozzle 21b may be provided so as to gradually decrease toward the first nozzle 21a. As a result, for example, a step may not be formed between the first nozzle 21a and the second nozzle 21b, and the inner surface may be continuous. When the inner surfaces of the first nozzle 21a and the second nozzle 21b are continuous in this way, the first nozzle 21a means a portion where the opening shape is substantially the same in the Z direction.

The shape of the nozzle 21 when viewed in a plan view from the Z direction is not particularly limited, and may be a circle, an ellipse, a rectangle, a polygon, a daruma shape, or the like.

Such a nozzle plate 20 can be formed of, for example, a metal such as stainless steel (SUS), an organic substance such as a polyimide resin, or a flat plate material such as silicon. The thickness of the nozzle plate 20 is preferably 60 μm or more and 100 μm or less. By using the nozzle plate 20 having such a thickness, the handleability of the nozzle plate 20 can be improved and the assembling property of the recording head 1 can be improved. By the way, by shortening the length of the nozzle 21 in the Z direction, it is possible to reduce the portion of the nozzle 21 that is not affected by the circulation flow when the ink is circulated, but the nozzle 21 is in the Z direction. In order to shorten the length of the nozzle plate 20, it is necessary to reduce the thickness of the nozzle plate 20 in the Z direction. When the thickness of the nozzle plate 20 is reduced in this way, the rigidity of the nozzle plate 20 is reduced, the deformation of the nozzle plate 20 causes variations in the ejection direction of ink droplets, and the ease of handling of the nozzle plate 20 is reduced. Is likely to decrease. That is, by using the nozzle plate 20 having a certain thickness as described above, the decrease in the rigidity of the nozzle plate 20 is suppressed, the ejection direction varies due to the deformation of the nozzle plate 20, and the handleability is deteriorated. It is possible to suppress a decrease in assembling property due to.

In the present embodiment, the communication plate 15 has a first communication plate 151 and a second communication plate 152. The first communication plate 151 and the second communication plate 152 are laminated in the Z direction so that the −Z side is the first communication plate 151 and the + Z side is the second communication plate 152.

The first communication plate 151 and the second communication plate 152 constituting such a communication plate 15 can be manufactured of a metal such as stainless steel, glass, a ceramic material, or the like. The communication plate 15 is preferably made of a material having substantially the same coefficient of thermal expansion as that of the flow path forming substrate 10. In the present embodiment, the communication plate 15 is formed by using a silicon single crystal substrate made of the same material as the flow path forming substrate 10. ..

The communication plate 15 includes a first communication portion 16 that communicates with the first liquid chamber portion 41 of the case member 40 to form a part of the first common liquid chamber 101, and a second liquid chamber portion 42 of the case member 40. A second communication portion 17 and a third communication portion 18 that communicate with each other and form a part of the second common liquid chamber 102 are provided. Further, as will be described in detail later, the communication plate 15 has a flow path that communicates the first common liquid chamber 101 and the pressure chamber 12, a flow path that communicates the pressure chamber 12 and the nozzle 21, and the nozzle 21 and the first. 2 A flow path communicating with the common liquid chamber 102 is provided. These flow paths provided in the communication plate 15 form a part of the individual flow paths 200.

The first communication portion 16 is provided at a position overlapping the first liquid chamber portion 41 of the case member 40 in the Z direction, and opens on both the + Z side surface and the −Z side surface of the communication plate 15. The communication plate 15 is provided so as to penetrate in the Z direction. The first communication portion 16 communicates with the first liquid chamber portion 41 on the −Z side to form the first common liquid chamber 101. That is, the first common liquid chamber 101 is composed of the first liquid chamber portion 41 of the case member 40 and the first communication portion 16 of the communication plate 15. Further, the first communication portion 16 extends in the −Y direction to a position where it overlaps the pressure chamber 12 in the Z direction on the + Z side. The first common liquid chamber 101 may be configured by the first liquid chamber portion 41 of the case member 40 without providing the first communication portion 16 on the communication plate 15.

The second communication portion 17 is provided at a position overlapping the second liquid chamber portion 42 of the case member 40 in the Z direction, and is provided so as to open on the −Z side surface of the first communication plate 151. Further, the second communication portion 17 is provided so as to be widened toward the nozzle 21 in the + Y direction on the + Z side.

The third communication portion 18 is provided so as to penetrate the second communication plate 152 in the Z direction so that one end communicates with a portion of the second communication portion 17 that is widened in the + Y direction. The opening on the + Z side of the third communication portion 18 is covered with a nozzle plate 20. That is, by providing the second communication portion 17 on the first communication plate 151, only the opening on the + Z side of the third communication portion 18 can be covered with the nozzle plate 20, so that the nozzle plate 20 has a relatively narrow area. It can be provided in, and the cost can be reduced.

The second common liquid chamber 102 is composed of the second communication portion 17 and the third communication portion 18 provided on the communication plate 15, and the second liquid chamber portion 42 provided on the case member 40. The second common liquid chamber 102 may be configured by the second liquid chamber portion 42 of the case member 40 without providing the second communication portion 17 and the third communication portion 18 on the communication plate 15.

A compliance board 49 having a compliance unit 494 is provided on the + Z side surface of the communication plate 15 on the + Z side where the first communication portion 16 opens. The compliance board 49 seals the opening on the nozzle surface 20a side of the first common liquid chamber 101.

In this embodiment, such a compliance substrate 49 includes a sealing film 491 made of a thin film having flexibility and a fixed substrate 492 made of a hard material such as metal. Since the region of the fixed substrate 492 facing the first common liquid chamber 101 is an opening 493 completely removed in the thickness direction, a part of the wall surface of the first common liquid chamber 101 is made flexible. The compliance portion 494 is a flexible portion sealed only by the sealing film 491. By providing the compliance unit 494 on a part of the wall surface of the first common liquid chamber 101 in this way, the pressure fluctuation of the ink in the first common liquid chamber 101 can be absorbed by the compliance unit 494 being deformed.

Further, the flow path forming substrate 10, the communication plate 15, the nozzle plate 20, the compliance substrate 49 and the like constituting the flow path substrate are communicated with the first common liquid chamber 101 and the second common liquid chamber 102, and the first A plurality of individual flow paths 200 for sending the ink of the common liquid chamber 101 to the second common liquid chamber 102 are provided. Here, each individual flow path 200 of the present embodiment communicates with the first common liquid chamber 101 and the second common liquid chamber 102, and is provided for each nozzle 21 and includes the nozzle 21. A plurality of such individual flow paths 200 are juxtaposed along the X direction, which is the juxtaposition direction of the nozzles 21. The two individual flow paths 200 adjacent to each other in the X direction, which is the parallel direction of the nozzles 21, are provided so as to communicate with the first common liquid chamber 101 and the second common liquid chamber 102, respectively. That is, the plurality of individual flow paths 200 provided for each nozzle 21 are provided so as to communicate with each other only in the first common liquid chamber 101 and the second common liquid chamber 102, respectively, and the plurality of individual flow paths 200 are the first. There is no communication with each other except for the 1 common liquid chamber 101 and the 2nd common liquid chamber 102. That is, in the present embodiment, the flow path provided with one nozzle 21 and one pressure chamber 12 is referred to as an individual flow path 200, and each individual flow path 200 communicates with the first common liquid chamber 101 and the second common liquid. It is provided so as to communicate only with the room 102.

As shown in FIGS. 2 and 3, the individual flow path 200 includes a nozzle 21, a pressure chamber 12, a first flow path 201, a second flow path 202, and a supply path 203.

The pressure chamber 12 is provided between the recess provided in the flow path forming substrate 10 and the communication plate 15 as described above, and extends in the Y direction. That is, in the pressure chamber 12, the supply path 203 is connected to one end in the Y direction and the second flow path 202 is connected to the other end in the Y direction so that the ink flows in the pressure chamber 12 in the Y direction. It is provided in. That is, the extending direction of the pressure chamber 12 is the direction in which the ink flows in the pressure chamber 12.

In the present embodiment, only the pressure chamber 12 is formed on the flow path forming substrate 10, but the present invention is not particularly limited to this, and the end portion on the upstream side of the pressure chamber 12, that is, the end portion in the + Y direction. A flow path resistance imparting portion having a cross-sectional area smaller than that of the pressure chamber 12 may be provided so as to impart the flow path resistance.

The supply path 203 connects the pressure chamber 12 and the first common liquid chamber 101, and is provided so as to penetrate the first communication plate 151 in the Z direction. The supply path 203 communicates with the first common liquid chamber 101 at the end on the + Z side and communicates with the pressure chamber 12 at the end on the −Z side. That is, the supply path 203 extends in the Z direction. Here, the direction in which the supply path 203 extends is the direction in which the ink flows in the supply path 203.

The first flow path 201 is provided between the pressure chamber 12 and the first flow path 201 so as to extend in the + Z direction, which is the first direction. The direction in which the second flow path 202 extends is the direction in which the ink flows in the first flow path 201. That is, the first direction in which the first flow path 201 extends is the + Z direction in the present embodiment. In this embodiment, such a first flow path 201 is provided so as to penetrate the communication plate 15 in the Z direction, communicate with the pressure chamber 12 at the end in the −Z direction, and communicate with the pressure chamber 12 at the end in the + Z direction. It communicates with the nozzle 21. In addition, the direction in which the second flow path 202 extends is the + Z direction includes a case in which the first flow path 201 has a vector whose extension direction is a component in the + Z direction. That is, the first flow path 201 may be inclined with respect to the + Z direction as long as it is not stretched in the X direction or the Y direction and does not contain any component in the + Z direction.

Further, the first flow path 201 refers to a portion formed in the communication plate 15. That is, the first flow path 201 is from the bottom surface of the pressure chamber 12 in the + Z direction to the portion covered with the nozzle plate 20.

Such a first flow path 201 has a downstream side first flow path 201a close to the nozzle 21 and an upstream side first flow path 201b closer to the pressure chamber 12 than the downstream side first flow path 201a. That is, the first flow path 201 has the downstream side first flow path 201a on the + Z side and the upstream side first flow path 201b on the −Z side.

The central axis C1 of the downstream first flow path 201a is located closer to the third direction, which is the opposite direction of the second direction, than the central axis C2 of the upstream first flow path 201b. Here, the second direction is a direction that intersects the + Z direction, which is the first direction, and is a direction in which the second flow path 202, which will be described in detail, extends. The second direction of this embodiment is the −Y direction. Therefore, the third direction, which is the opposite direction of the second direction of the present embodiment, is the + Y direction. Therefore, the central axis C1 of the downstream first flow path 201a is located closer to the + Y direction than the central axis C2 of the upstream first flow path 201b.

Here, the central axis C1 of the downstream first flow path 201a is an axis passing through the center of the downstream first flow path 201a when the opening shape is circular when viewed in a plan view from the Z direction. is there. Further, when the opening shape when the downstream first flow path 201a is viewed in a plan view from the Z direction is a shape other than a circle, for example, an ellipse, an egg, a rectangle, a polygon, or a daruma, the downstream side. The central axis C1 of the first flow path 201a is an axis passing through the center of gravity of the area.

The downstream first flow path 201a of the present embodiment is formed so that the opening shape is the same in the Z direction. That is, the cross-sectional shape and cross-sectional area of the downstream first flow path 201a in the surface direction including the X direction and the Y direction are the same over the Z direction. Therefore, the central axis C1 is along the line connecting the center of the opening on the + Z side and the center of the opening on the −Z side, that is, the axis along the + Z direction. Further, the downstream side first flow path 201a is not limited to this, and for example, when the downstream side first flow path 201a is provided so as to be inclined with respect to the + Z direction, the central axis C1 is on the downstream side. It refers to a line along a line inclined with respect to the + Z direction connecting the center of the opening on the −Z side of the first flow path 201a and the center of the opening on the + Z side.

Similarly, the central axis C2 of the upstream first flow path 201b is an axis passing through the center of the upstream first flow path 201b when the opening shape is circular when viewed in a plan view from the Z direction. is there. Further, when the opening shape when the upstream side first flow path 201b is viewed in a plan view from the Z direction is a shape other than a circle, for example, an elliptical shape, an oval shape, a rectangular shape, a polygonal shape, or a daruma shape, the upstream side The central axis C2 of the first flow path 201b is an axis passing through the center of gravity of the area.

The upstream first flow path 201b of the present embodiment is formed so that the opening shape is the same in the Z direction. That is, the cross-sectional shape and cross-sectional area of the upstream first flow path 201b in the surface direction including the X direction and the Y direction are the same over the Z direction. Therefore, the central axis C2 is along the line connecting the center of the opening on the + Z side and the center of the opening on the −Z side, that is, the axis along the + Z direction. Further, the upstream side first flow path 201b is not limited to this, and for example, when the upstream side first flow path 201b is provided so as to be inclined with respect to the + Z direction, the central axis C2 is in the + Z direction. It will be inclined with respect to. Therefore, the central axis C2 refers to the one along the line connecting the center of the opening on the −Z side of the upstream first flow path 201b and the center of the opening on the + Z side.

Further, in the present embodiment, the downstream side first flow path 201a and the upstream side first flow path 201b are formed so that the cross-sectional shapes and cross-sectional areas in the surface direction including the X direction and the Y direction are substantially the same. Of course, the present invention is not limited to this, and the cross-sectional shape and cross-sectional area of the downstream first flow path 201a and the upstream side first flow path 201b may be different.

Such a downstream side first flow path 201a is provided in the second communication plate 152, which is a second flow path substrate. That is, the downstream first flow path 201a is provided so as to penetrate in the Z direction from the −Z side surface to the + Z side surface of the second communication plate 152. Further, the downstream first flow path 201a has a rectangular opening shape in a plan view from the Z direction.

Further, the upstream side first communication board 201b is provided in the first communication board 151 which is a first communication board different from the second communication board 152 which is the second communication board. That is, the upstream side first flow path 201b is provided so as to penetrate the first communication plate 151 from the −Z side surface to the + Z side surface in the Z direction. Further, the upstream first flow path 201b has a rectangular opening shape in a plan view from the Z direction.

In this way, by providing the downstream side first flow path 201a and the upstream side first flow path 201b on the second communication plate 152 and the first communication plate 151, which are different flow path substrates, the downstream side first flow path 201a is provided. The central axis C1 of 201a can be easily arranged closer to the + Y direction, which is the third direction, with respect to the central axis C2 of the upstream first flow path 201b.

Then, as described above, the central axis C1 of the downstream first flow path 201a is located closer to the + Y direction than the central axis C2 of the upstream first flow path 201b.

Further, as shown in FIGS. 3 and 4, in the present embodiment, the position 201b1 in the −Y direction, which is the second most direction on the inner surface of the upstream side first flow path 201b, is the downstream side first flow path 201a. It is closer to the -Y direction than the position 201a1 in the most -Y direction on the inner surface. The position 201b1 in the −Y direction, which is the second most direction on the inner surface of the upstream side first flow path 201b, is the upstream side first flow when the upstream side first flow path 201b is viewed in a plan view from the Z direction. This is the position of the road 201b in the most −Y direction.

Further, in the present embodiment, the position 201b2 in the + Y direction, which is the thirdmost direction on the inner surface of the upstream first flow path 201b, is larger than the position 201a2 in the most + Y direction on the inner surface of the downstream first flow path 201a. , -Y direction. The position 201a1 in the −Y direction, which is the second most direction on the inner surface of the first downstream flow path 201a, is the most −Y direction when the first downstream flow path 201a is viewed in a plan view from the Z direction. It is the position that becomes.

In other words, the first flow path 201 is provided with a wall 201c protruding in the + Y direction from the inner side surface of the downstream side first flow path 201a in the −Y direction with respect to the inner surface of the upstream side first flow path 201b. , A groove 201d recessed in the + Y direction is formed on the inner surface in the + Y direction.

The nozzle 21 is arranged at a position communicating with the end of the first flow path 201. That is, the nozzle 21 is arranged at a position overlapping the first flow path 201 when viewed in a plan view from the Z direction. As a result, ink droplets are ejected from the nozzle 21 in the + Z direction.

The second flow path 202 is provided extending in the −Y direction between the supply port 43 and the discharge port 44. The direction in which the second flow path 202 extends is the direction in which the ink flows in the second flow path 202. That is, in the present embodiment, the second direction in which the second flow path 202 extends is the −Y direction. Such a second flow path 202 communicates with the second flow path 202 at the end in the + Y direction and communicates with the third communication portion 18 of the second common liquid chamber 102 at the end in the −Y direction.

The second flow path 202 of the present embodiment is provided between the second communication plate 152 and the nozzle plate 20. Specifically, the second flow path 202 is formed by providing a recess in the second communication plate 152 and covering the opening of the recess with a nozzle plate 20. The second flow path 202 is not particularly limited to this, and a recess may be provided in the nozzle plate 20 and the recess of the nozzle plate 20 may be covered with the second communication plate 152. Recessions may be provided on both the nozzle plate 20 and the nozzle plate 20.

In the present embodiment, the second flow path 202 is provided so that the cross-sectional area across the ink flowing through the flow path, that is, the cross-sectional area in the surface direction including the X direction and the Z direction has the same area over the Y direction. Has been done. The second flow path 202 may be provided so that the cross-sectional areas crossing the sections have different areas in the Y direction. By the way, the difference in the area crossing the second flow path 202 includes the case where the height in the Z direction is different, the case where the width in the X direction is different, and the case where both are different.

Further, the cross-sectional shape of the second flow path 202 that crosses the flow path, that is, the cross-sectional shape in the surface direction including the X direction and the Z direction is rectangular. The cross-sectional shape of the second flow path 202 that crosses the flow path is not particularly limited, and may be trapezoidal, semicircular, semi-elliptical, or the like.

It is preferable that the cross-sectional area across the ink flowing through the second flow path 202 is smaller than the cross-sectional area across the ink flowing through the first flow path 201. The cross-sectional area crossing the first flow path 201 is the area of the cross section in the plane direction including the X direction and the Y direction. The cross-sectional area crossing the second flow path 202 is the area of the cross section in the plane direction including the X direction and the Z direction. By making the cross-sectional area of the second flow path 202 relatively small in this way, the individual flow paths 200 can be arranged at a high density in the X direction, and the nozzles 21 can be arranged at a high density in the X direction. It is possible to prevent the recording head 1 from becoming larger in the Z direction. Further, by making the cross-sectional area of the first flow path 201 relatively large, it is possible to suppress the flow path resistance from the pressure chamber 12 to the nozzle 21 from becoming small, and the liquid discharge characteristics, particularly the discharged droplets, are suppressed. It is possible to suppress a decrease in weight. In particular, by expanding the first flow path 201 in the Y direction and increasing the cross-sectional area of the first flow path 201, the flow path resistance of the first flow path 201 can be reduced and the individual flow paths 200 have a high density. Can be placed in.

Such individual flow paths 200 include the supply path 203, the pressure chamber 12, the first flow path 201, in order from the upstream side communicating with the first common liquid chamber 101 to the downstream side communicating with the second common liquid chamber 102. It has a second flow path 202. Then, in such an individual flow path 200, so-called circulation is performed in which ink flows from the first common liquid chamber 101 through the individual flow path 200 to the second common liquid chamber 102. Further, by driving the piezoelectric actuator 300, a pressure change is caused in the ink in the pressure chamber 12, and the pressure of the ink in the nozzle 21 is increased, so that ink droplets are ejected from the nozzle 21 to the outside. When ink flows from the first common liquid chamber 101 through the individual flow path 200 to the second common liquid chamber 102, the piezoelectric actuator 300 may be driven, or the first common liquid chamber 101 passes through the individual flow path 200 and passes through the individual flow path 200. 2 The piezoelectric actuator 300 may be driven when the ink does not flow into the common liquid chamber 102. Further, the ink may temporarily flow from the second common liquid chamber 102 to the first common liquid chamber 101 due to the pressure change due to the drive of the piezoelectric actuator 300.

Then, in the present embodiment, the first flow path 201 is provided with the downstream side first flow path 201a and the upstream side first flow path 201b, so that the upstream side first flow path 201 is provided during circulation as shown in FIG. At the connecting portion between the path 201b and the downstream first flow path 201a, the ink flux can be bent in the + Y direction opposite to the −Y direction, which is the extension direction of the second flow path. Therefore, at the connection portion between the downstream first flow path 201a and the second flow path 202, the ink flow direction is bent in the −Y direction and the ink ejection direction is formed in the downstream first flow path 201a. It is possible to generate an ink vortex in the + Z direction. In this way, a flow toward the + Z side is generated in the first flow path 201a on the downstream side, and the ink in the first flow path 201 is allowed to enter the nozzle 21, particularly the second nozzle 21b, in the nozzle 21. Ink flow can be created. By causing the ink to flow in the nozzle 21 in this way, the velocity gradient of the ink in the nozzle 21 can be increased, and the ink in the nozzle 21 can be replaced with new ink supplied from the upstream. Therefore, it is difficult for the ink in the nozzle 21 to thicken due to drying, and even if the ink in the nozzle 21 thickens, it flows downstream in the first flow path 201, so that the thickened ink remains in the nozzle 21. It is possible to suppress the variation in the ejection direction of the ink droplets due to the ink droplets, and to suppress the deviation of the landing position of the ink droplets on the injection medium.

On the other hand, as shown in FIG. 6, when the first flow path 201 is provided in a straight line along the + Z direction, the ink flowing in the Y direction through the first flow path 201 is difficult to enter into the nozzle 21, and the nozzle. Ink stays in 21. When ink stays in the nozzle 21 in this way, thickening tends to occur due to drying of the stayed ink. Therefore, the thickened ink causes variations in the ejection direction of the ink droplets ejected from the nozzle 21, and the ejection position of the ejected ink droplets tends to shift to the injection medium. Further, among the corners formed by the side surface of the first flow path 201 and the nozzle plate 20, the ink stays in the corner D in the + Y direction, which is the opposite side of the second flow path 202, and the ink component. Settlement and air bubbles will stay. Ink and air bubbles accumulated in such corners D invade into the nozzle 21, and the components of the ejected ink droplets vary, and the air bubbles cause deviations in the flight direction of the ink droplets and ejection defects. It will be easier.

Further, in the present embodiment, as shown in FIGS. 3 and 4, the central axis C1 of the downstream first flow path 201a is third than the central axis C3 of the opening 211 on the first flow path 201 side of the nozzle 21. It is preferably located closer to the + Y direction, which is the direction.

The central axis C3 of the opening 211 on the first flow path 201 side of the nozzle 21 is an axis that passes through the center of the opening 211 and is along the Z direction when the opening 211 is circular. When the opening 211 has a shape other than a circle, for example, an ellipse, an oval, a rectangle, a polygon, or a daruma shape, the central axis C3 of the opening 211 passes through the center of gravity of the area of the opening 211 and is in the Z direction. It is the axis along.

By arranging the central axis C1 of the downstream first flow path 201a closer to the central axis C3 of the opening 211 of the nozzle 21 in the + Y direction, the inner side surface of the downstream first flow path 201a is arranged in the + Y direction. The nozzle 21 can be moved away from the position 201a2 on the inner side surface of the nozzle 21 from the place where the ink on the corner D formed by the inner side surface on the + Y side of the downstream first flow path 201a and the nozzle plate 20 stays. You can keep it away. Therefore, the ink and the retained air bubbles that have accumulated in the corner D formed by the + Y side inner surface of the downstream first flow path 201a and the nozzle plate 20 and have settled are difficult to enter into the nozzle 21, and are ejected. It is possible to suppress variations in the components of the ink droplets, deviation of the ink droplets in the flight direction due to bubbles, and ejection defects.

Further, as shown in FIGS. 3 and 4, the position 211a in the −Y direction, which is the second most direction in the opening 211 of the nozzle 21 on the first flow path 201 side, is on the inner surface of the downstream first flow path 201a. It is preferable that the position is closer to the −Y direction than the position 201a1 in the −Y direction. That is, in the cross section shown in FIG. 3, the position 201a1 in the most −Y direction on the inner surface of the downstream first flow path 201a is preferably arranged at a position facing the opening 211 of the nozzle 21 in the Z direction. .. As a result, it is possible to facilitate ink that bends from the + Z direction to the −Y direction at the connection portion between the downstream first flow path 201a and the second flow path 202 into the opening 211 of the nozzle 21.

Further, as shown in FIGS. 3 and 4, the position 211b on the + Y direction side, which is the thirdmost direction in the opening 211 on the first flow path 201 side of the nozzle 21, is on the inner surface of the downstream first flow path 201a. It is preferable that the position is closer to the −Y direction than the position 201a2 on the most + Y side.
In this way, by setting the position 211b of the opening 211 of the nozzle 21 in the + Y direction closer to the position 201a2 on the + Y side of the downstream first flow path 201a in the −Y direction, the opening 211 of the nozzle 21 communicates with the second communication. It can be prevented from being covered by the plate 152.

As described above, the inkjet recording head 1, which is an example of the liquid injection head of the present embodiment, has a supply port 43 and a discharge port 44 for liquid ink, and one of the supply port 43 and the discharge port 44. Between the pressure chamber 12 which is a pressure chamber communicating with the pressure chamber 12, the nozzle 21 for discharging the ink pressurized in the pressure chamber 12, and the pressure chamber 12 and the nozzle 21, toward the + Z direction which is the first direction. A second flow path 201 that communicates with the other of the supply port 43 and the discharge port 44, branches from the first flow path 201, and extends in the −Y direction, which is the second direction intersecting + Z. The first flow path 201 includes a flow path 202, and the first flow path 201 includes a first flow path 201a on the downstream side close to the nozzle 21 and a first flow path 201b on the upstream side closer to the pressure chamber 12 than the first flow path 201a on the downstream side. The central axis C1 of the downstream first flow path 201a is located closer to the + Y direction, which is the third direction opposite to the −Y direction, than the central axis C2 of the upstream first flow path 201b. ing.

The first flow path 201 extending in the Y direction is composed of the downstream side first flow path 201a and the upstream side first flow path 201b, and the central axis C1 of the downstream side first flow path 201a is on the upstream side. By arranging the first flow path 201b closer to the + Y direction than the central axis C2, the ink flowing in the + Z direction in the first flow path 201 is bent in the + Y direction, and the ink flows from the first flow path 201 to the second flow path. The ink flowing in the + Z direction can be bent in the −Y direction to form a vortex of ink toward the nozzle 21 in the first flow path 201. Therefore, the ink can be flowed toward the nozzle 21 to cause the ink to flow in the nozzle 21, and the ink in the nozzle 21 can be replaced with the new ink supplied from the upstream. Therefore, the accumulation of ink in the nozzle 21 is suppressed, and the accumulated ink thickens, resulting in clogging of the nozzle 21 and ejection defects such as deviation of the ink droplets ejected from the nozzle 21 in the flight direction. Can be suppressed.

Further, by arranging the central axis C1 of the downstream first flow path 201a closer to the + Y direction than the central axis C2 of the upstream first flow path 201b, the corner D between the first flow path 201 and the nozzle plate 20 The nozzle 21 can be arranged away from the portion where the ink stays, such as ink, and the ink or bubbles whose components have settled due to the retention are difficult to move to the nozzle 21 side. Therefore, it is possible to suppress clogging of the nozzle 21 and variation in the components of the ink droplets ejected from the nozzle 21 due to ink or air bubbles that have accumulated and settled components.

Further, by communicating the nozzle 21 with the first flow path 201 without communicating with the middle of the second flow path 202 extending in the −Y direction, the flow path resistance from the pressure chamber 12 to the nozzle 21 is increased. It is difficult to increase, and it is possible to prevent the weight of the ink droplets ejected from the nozzle 21 from becoming small. Therefore, it is not necessary to drive the piezoelectric actuator 300 with a higher drive voltage, and the discharge efficiency can be improved. Of course, the nozzle 21 may be arranged at a position where it communicates with the middle of the second flow path 202.

Further, in the recording head 1 of the present embodiment, the position 201b1 on the Y-direction side, which is the second most direction on the inner surface of the upstream first flow path 201b, is the most − on the inner surface of the downstream first flow path 201a. It is preferable that the position is closer to the −Y direction than the position 201a1 on the Y direction side. As a result, the ink flowing in the + Z direction in the first flow path 201 can be bent in the + Y direction, and a vortex can be generated.

Further, in the recording head 1 of the present embodiment, the position 201b2 on the + Y direction side, which is the thirdmost direction on the inner surface of the upstream side first flow path 201b, is the most + Y direction on the inner surface of the downstream side first flow path 201a. It is preferable that the position is closer to the −Y direction than the position 201a2 on the side. As a result, the ink flowing in the + Z direction in the first flow path 201 can be further bent in the + Y direction to generate a vortex flow.

Further, in the recording head 1 of the present embodiment, the upstream side first flow path 201b is formed on the first communication plate 151 which is the first flow path substrate, and the downstream side first flow path 201a is the first communication plate. It is preferable that the nozzle 21 is formed on the second communication plate 152, which is a second flow path substrate different from 151, and the nozzle 21 is formed on the nozzle plate 20 which is a nozzle substrate. By forming the upstream side first flow path 201b, the downstream side first flow path 201a, and the nozzle 21 on different substrates in this way, the central axes C1 and C2 can be easily arranged at different positions.

Further, in the recording head 1 of the present embodiment, the central axis C1 of the downstream first flow path 201a is closer to the + Y direction, which is the third direction than the central axis C3 of the opening 211 on the first flow path 201 side of the nozzle 21. It is preferably located in. According to this, the nozzle 21 and the side surface of the downstream side first flow path 201a in the + Y direction can be arranged apart from each other, and the ink at the corner between the side surface of the downstream side first flow path 201a and the nozzle plate 20 can be arranged. The nozzle 21 can be separated from the stagnant portion. Therefore, it is possible to suppress the stagnant ink and air bubbles from entering the nozzle 21, and it is possible to suppress the variation in the components of the ink droplets, the variation in the flight direction of the ink droplets, and the ejection defects such as clogging.

Further, in the recording head 1 of the present embodiment, the position 211a on the −Y direction side, which is the second most direction in the opening 211 on the first flow path 201 side of the nozzle 21, is on the inner surface of the downstream first flow path 201a. It is preferable that the position is closer to the −Y direction than the position 201a1 on the most −Y direction side. According to this, the opening 211 of the nozzle 21 can be made to face the position 201a1 on the −Y direction side of the downstream side first flow path 201a in the Z direction, and the downstream side first flow path 201a to the second flow path 201a can be opposed to each other. It is possible to facilitate the flow of ink toward 202 into the nozzle 21.

Further, in the recording head 1 of the present embodiment, the position 211b on the + Y direction side, which is the thirdmost direction in the opening 211 on the first flow path 201 side of the nozzle 21, is the most on the inner surface of the first flow path 201a on the downstream side. It is preferable that the position is closer to the −Y direction than the position 201a2 on the + Y direction side. According to this, it is possible to prevent the opening 211 of the nozzle 21 from being covered by the communication plate 15.

In this embodiment, the ink flow will be described on the premise that the ink flows from the first common liquid chamber 101 to the second common liquid chamber 102 via the pressure chamber 12, the first flow path 201, and the second flow path 202. However, the ink flows sequentially from the second common liquid chamber 102 to the second flow path 202, the first flow path 201, the pressure chamber 12, and the first common liquid chamber 101 so that the flow in the opposite direction occurs. The recording head 1 can also be used as described above. Even in such a case, the streamline of ink from the second flow path 202 to the first flow path 201 is generated directly above the nozzle 21, so that the ink in the vicinity of the nozzle 21 can be efficiently used. It can be collected.

(Embodiment 2)
FIG. 7 is an enlarged cross-sectional view of a main part of an inkjet recording head, which is an example of the liquid injection head according to the second embodiment of the present invention. The same members as those in the above-described embodiment are designated by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 7, the communication plate 15 is provided with a first flow path 201 extending in the + Z direction.

The first flow path 201 has a downstream side first flow path 201a close to the nozzle 21 and an upstream side first flow path 201b closer to the pressure chamber 12 than the downstream side first flow path 201a.

In the present embodiment, the diameter of the upstream side first flow path 201b is larger than the diameter of the downstream side first flow path 201a.

Here, the diameter of the first flow path 201a on the downstream side is the width dimension of the widest portion in the Y direction of the opening when viewed in a plan view from the Z direction. That is, when the opening shape of the downstream side first flow path 201a is circular, the diameter of the downstream side first flow path 201a is the diameter. When the opening shape of the downstream first flow path 201a is a shape other than a circle, for example, an ellipse, an egg shape, a rectangle, a polygon, or a daruma shape, what is the diameter of the downstream first flow path 201a? , The width dimension of the widest part of the opening in the Y direction.

Similarly, the diameter of the upstream first flow path 201b is the width dimension of the widest portion in the Y direction of the opening when viewed in a plan view from the Z direction. That is, when the opening shape of the upstream side first flow path 201b is circular, the diameter of the upstream side first flow path 201b is the diameter. Further, when the opening shape of the upstream side first flow path 201b is a shape other than a circle, for example, an elliptical shape, an egg shape, a rectangular shape, a polygonal shape, a daruma shape, etc., what is the diameter of the upstream side first flow path 201b? , The width dimension of the widest part of the opening in the Y direction.

The central axis C1 of the downstream first flow path 201a is located closer to the + Y direction than the central axis C2 of the upstream first flow path 201b. In the present embodiment, the position 201b1 in the most −Y direction on the inner surface of the upstream first flow path 201b is closer to the −Y direction than the position 201a1 in the most −Y direction on the inner surface of the downstream first flow path 201a. It has become. Further, the position 201b2 in the most + Y direction on the inner surface of the upstream first flow path 201b is closer to the + Y direction than the position 201a2 in the most + Y direction on the inner surface of the downstream first flow path 201a.

That is, the first flow path 201 is provided with a wall 201c protruding in the + Y direction from the inner side surface of the downstream side first flow path 201a in the −Y direction with respect to the inner surface of the upstream side first flow path 201b. A wall 201e protruding in the −Y direction from the inner surface in the + Y direction is formed. Since the central axis C1 of the downstream first flow path 201a is located closer to the central axis C2 of the upstream first flow path 201b in the + Y direction, the wall 201c is in the + Y direction with respect to the inner surface of the upstream first flow path 201b. The amount of protrusion to the wall 201e with respect to the inner surface of the upstream first flow path 201b is larger than the amount of protrusion of the wall 201e in the −Y direction.

Therefore, the ink flowing in the + Z direction in the first flow path 201 can be bent in the + Y direction at the connection portion from the upstream side first flow path 201b to the downstream side first flow path 201a. Therefore, it is possible to form an ink vortex toward the nozzle 21 in the first flow path 201, generate an ink flow toward the nozzle 21, and efficiently collect the ink in the vicinity of the nozzle 21. ..

(Embodiment 3)
FIG. 8 is an enlarged cross-sectional view of a main part of an inkjet recording head, which is an example of the liquid injection head according to the third embodiment of the present invention. The same members as those in the above-described embodiment are designated by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 8, the communication plate 15 has a first communication plate 151, a second communication plate 152, and a third communication plate 153.

The second communication plate 152 is arranged on the + Z side, which is the nozzle plate 20 side.
The first communication plate 151 is arranged on the −Z side of the second communication plate 152.
Further, the third communication plate 153 is arranged on the −Z side of the first communication plate 151. That is, the third communication plate 153, the first communication plate 151, and the second communication plate 152 are laminated in this order from the −Z side to the + Z side.

The first flow path 201 includes a downstream side first flow path 201a, an upstream side first flow path 201b, and a connection first flow path 201f.

The downstream side first flow path 201a is arranged at a position close to the nozzle 21, in the present embodiment, on the most + Z side of the first flow path 201. As a result, the + Z side end of the downstream first flow path 201a communicates with the nozzle 21.

The upstream side first flow path 201b is arranged closer to the pressure chamber 12 than the downstream side first flow path 201a, and is provided so as to communicate with the −Z side end of the downstream side first flow path 201a. ing.

The connection first flow path 201f is arranged closer to the pressure chamber 12 than the upstream side first flow path 201b, and is provided so as to communicate with the −Z side end of the upstream side first flow path 201b. ing. That is, the first flow path 201 is arranged in the order of the connection first flow path 201f, the upstream side first flow path 201b, and the downstream side first flow path 201a from the −Z side to the + Z side.

That is, the upstream side first flow path 201b may be arranged closer to the pressure chamber 12 than the downstream side first flow path 201a, and as in the above-described first and second embodiments, the upstream side first flow path 201b May be directly connected to the pressure chamber 12, or may be connected to the pressure chamber 12 via the connection first flow path 201f as in the present embodiment.

Further, in the present embodiment, the downstream side first flow path 201a is provided at the + Z side end of the first flow path 201 so that the downstream side first flow path 201a directly communicates with the nozzle 21, but the downstream side. The first flow path 201a is not particularly limited as long as it is provided at a position close to the nozzle 21, and for example, another flow path is provided between the downstream side first flow path 201a and the nozzle 21. May be good. That is, when the downstream side first flow path 201a is provided at a position closer to the nozzle 21, the downstream side first flow path 201a is provided at a position closer to the nozzle 21 than the upstream side first flow path 201b. Say that you are.

The central axis C1 of the downstream first flow path 201a is located closer to the + Y direction than the central axis C2 of the upstream first flow path 201b.

Further, the central axis C2 of the upstream first flow path 201b is located closer to the + Y direction than the central axis C4 of the connection first flow path 201f.
That is, the central axes of the connection first flow path 201f, the upstream side first flow path 201b, and the downstream side first flow path 201a, which are provided in order from the −Z direction to the + Z direction, gradually move toward the + Y direction. As such, it is provided in a so-called staircase shape.

Even with such a configuration, the ink flowing in the + Z direction in the first flow path 201 can be bent in the + Y direction, and a vortex flow toward the second flow path 202 is formed in the first flow path 201. Ink can flow toward the nozzle 21. Therefore, the ink in the vicinity of the nozzle 21 can be efficiently recovered.

(Other embodiments)
Although each embodiment of the present invention has been described above, the basic configuration of the present invention is not limited to the above.

For example, in the above-described first embodiment, the downstream side first flow path 201a and the upstream side first flow path 201b are provided on the second communication plate 152 and the first communication plate 151, which are different flow path substrates. However, the present invention is not particularly limited to this, and the downstream side first flow path 201a and the upstream side first flow path 201b may be provided on one communication plate 15. In this way, the downstream side first flow path 201a and the upstream side first flow path 201b are connected to one communication plate 15, and the central axis C1 of the downstream side first flow path 201a is the center of the upstream side first flow path 201b. In order to form the shaft C2 by arranging it closer to the + Y direction, which is the third direction, for example, etching may be performed from both the −Z side surface and the + Z side surface of the communication plate 15.

For example, in the above-described embodiment, the nozzles 21 are arranged side by side in the X direction orthogonal to both the Y direction and the Z direction, with the first axis direction as the Y direction and the second axis direction as the Z direction. The nozzle 21 and the pressure chamber 12 and the like may be arranged side by side in the in-plane direction of the nozzle surface 20a in a direction inclined with respect to the X direction.

Further, in the present embodiment, the first flow path 201 of the individual flow path 200 and the second common liquid chamber 102 are directly connected, but the present invention is not particularly limited to this, and the first flow path 201 and the second flow path 201 are second. Another flow path extending in the Z direction, which is the second axial direction, may be provided between the common liquid chamber 102 and the common liquid chamber 102.

Here, an example of an inkjet recording device, which is an example of the liquid injection device of the present embodiment, will be described with reference to FIG. Note that FIG. 9 is a diagram showing a schematic configuration of the inkjet recording device of the present invention.

As shown in FIG. 9, in the inkjet recording device I, which is an example of the liquid injection device, a plurality of recording heads 1 are mounted on the carriage 3. The carriage 3 on which the recording head 1 is mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. In the present embodiment, the moving direction of the carriage 3 is the Y direction, which is the first axis direction.

Further, the apparatus main body 4 is provided with a tank 2 which is a storage means for storing ink as a liquid. The tank 2 is connected to the recording head 1 via a supply pipe 2a such as a tube, and ink from the tank 2 is supplied to the recording head 1 via the supply pipe 2a. Further, the recording head 1 and the tank 2 are connected via a discharge pipe 2b such as a tube, and the ink discharged from the recording head 1 is returned to the tank 2 via the discharge pipe 2b, so-called circulation. Will be The tank 2 may be composed of a plurality of tanks 2.

Then, the driving force of the drive motor 7 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7a (not shown), so that the carriage 3 equipped with the recording head 1 is moved along the carriage shaft 5. On the other hand, the apparatus main body 4 is provided with a transport roller 8 as a transport means, and the recording sheet S, which is an injection medium such as paper, is transported by the transport roller 8. The transporting means for transporting the recording sheet S is not limited to the transport roller 8, and may be a belt, a drum, or the like. In the present embodiment, the transport direction of the recording sheet S is the X direction.

In the above-mentioned inkjet recording device I, the one in which the recording head 1 is mounted on the carriage 3 and moves in the main scanning direction is illustrated, but the present invention is not particularly limited to this, and for example, the recording head 1 is fixed and the recording head 1 is fixed. The present invention can also be applied to a so-called line-type recording device that prints by simply moving a recording sheet S such as paper in the sub-scanning direction.

Further, in each embodiment, an inkjet recording head has been described as an example of the liquid injection head, and an inkjet recording device has been described as an example of the liquid injection device. However, the present invention broadly describes the liquid injection head and the liquid injection device in general. Of course, it can also be applied to a liquid injection head and a liquid injection device that inject a liquid other than ink. Other liquid injection heads include, for example, various recording heads used in image recording devices such as printers, color material injection heads used in manufacturing color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material injection head used for forming an electrode, a bioorganic substance injection head used for biochip production, and the like, and the present invention can also be applied to a liquid injection device provided with such a liquid injection head.

Here, an example of the liquid injection system of the present embodiment will be described with reference to FIG. Note that FIG. 10 is a block diagram illustrating a liquid injection system of an inkjet recording device, which is the liquid injection device of the present invention.

As shown in FIG. 10, the liquid injection system includes the above-mentioned recording head 1 and a main tank 500 as a mechanism for supplying ink as a liquid to the supply port 43 and collecting the ink from the discharge port 44 to circulate the ink. The first tank 501, the second tank 502, the compressor 503, the vacuum pump 504, the first liquid feeding pump 505, and the second liquid feeding pump 506 are provided.

A recording head 1 and a compressor 503 are connected to the first tank 501, and the ink of the first tank 501 is supplied to the recording head 1 at a predetermined pressure by the compressor 503.

The second tank 502 is connected to the first tank 501 via the first liquid feeding pump 505, and the ink of the second tank 502 is fed to the first tank 501 by the first liquid feeding pump 505.

Further, the recording head 1 and the vacuum pump 504 are connected to the second tank 502, and the ink of the recording head 1 is discharged to the second tank 502 at a predetermined negative pressure by the vacuum pump 504.

That is, ink is supplied from the first tank 501 to the recording head 1, and ink is discharged from the recording head 1 to the second tank 502. Then, the ink is circulated by sending the ink from the second tank 502 to the first tank 501 by the first liquid feeding pump 505.

Further, the main tank 500 is connected to the second tank 502 via the second liquid feeding pump 506, and the ink consumed by the recording head 1 is replenished from the main tank 500 to the second tank 502. To. The ink from the main tank 500 to the second tank 502 may be replenished at a timing such as when the liquid level of the ink in the second tank 502 becomes lower than a predetermined height.

I ... Inkjet recording device (liquid injection device), 1 ... Inkjet recording head (liquid injection head), 2 ... Tank, 2a ... Supply pipe, 2b ... Discharge pipe, 3 ... Carriage, 4 ... Device body, 5 ... Carriage Shaft, 7 ... Drive motor, 7a ... Timing belt, 8 ... Conveying roller, 10 ... Flow path forming substrate, 12 ... Pressure chamber (pressurizing chamber), 15 ... Communication plate, 16 ... First communication part, 17 ... Second Communication part, 18 ... 3rd communication part, 20 ... Nozzle plate, 20a ... Nozzle surface, 21 ... Nozzle, 21a ... 1st nozzle, 21b ... 2nd nozzle, 211 ... Opening, 22 ... Nozzle row, 30 ... Protective substrate, 31 ... Piezoelectric actuator holding part, 32 ... Through hole, 40 ... Case member, 41 ... First liquid chamber part, 42 ... Second liquid chamber part, 43 ... Supply port, 44 ... Discharge port, 45 ... Connection port, 49 ... Compliance board, 50 ... Vibrating plate, 60 ... 1st electrode, 70 ... Piezoelectric layer, 80 ... 2nd electrode, 90 ... Lead electrode, 101 ... 1st common liquid chamber, 102 ... 2nd common liquid chamber, 120 ... Flexible Cable, 121 ... Drive circuit, 151 ... 1st communication plate, 152 ... 2nd communication plate, 153 ... 3rd communication plate, 200 ... Individual flow path, 201 ... 1st flow path, 201a ... Downstream 1st flow path, 201b ... upstream first flow path, 201c ... wall, 201d ... groove, 201e ... wall, 201f ... connection first flow path, 202 ... second flow path, 203 ... supply path, 300 ... piezoelectric actuator, 491 ... seal Still film, 492 ... Fixed substrate, 493 ... Opening, 494 ... Compliance part, 500 ... Main tank, 501 ... 1st tank, 502 ... 2nd tank, 503 ... Compressor, 504 ... Vacuum pump, 505 ... 1st liquid feed Pump, 506 ... 2nd liquid feed pump, S ... Recording sheet

Claims (9)

A liquid injection head having a liquid supply port and a liquid discharge port.
A pressurizing chamber communicating with one of the supply port and the discharge port,
A nozzle that discharges the liquid pressurized in the pressurizing chamber and
A first flow path extending in the first direction between the pressurizing chamber and the nozzle,
A second flow path that communicates with the other of the supply port and the discharge port, branches from the first flow path, and extends in the second direction intersecting the first direction.
The first flow path has a downstream side first flow path close to the nozzle and an upstream side first flow path closer to the pressurization chamber than the downstream side first flow path.
The liquid injection head is characterized in that the central axis of the downstream first flow path is located closer to the third direction, which is the opposite direction of the second direction, than the central axis of the upstream first flow path. .. The position on the inner side surface of the upstream side first flow path on the most second direction side is closer to the second direction than the position on the inner side surface of the downstream side first flow path on the most side in the second direction. The liquid injection head according to claim 1, wherein the liquid injection head is provided. The position on the inner side surface of the upstream side first flow path on the third direction side is closer to the second direction than the position on the inner side surface of the downstream side first flow path on the most side in the third direction. The liquid injection head according to claim 1 or 2, wherein the liquid injection head is provided. The liquid injection head according to any one of claims 1 to 3, wherein the diameter of the upstream side first flow path is larger than the diameter of the downstream side first flow path. The upstream first flow path is formed on the first flow path substrate.
The downstream first flow path is formed on a second flow path board different from the first flow path board.
The liquid injection head according to any one of claims 1 to 4, wherein the nozzle is formed on a nozzle substrate. Any one of claims 1 to 5, wherein the central axis of the downstream side first flow path is located closer to the third direction than the central axis of the opening of the nozzle on the first flow path side. The liquid injection head described in. The position of the nozzle on the first flow path side at the most second direction side is closer to the second direction than the position on the inner surface of the downstream side first flow path on the second direction side. The liquid injection head according to claim 6, wherein the liquid injection head is provided. The position on the third direction side of the opening on the first flow path side of the nozzle is closer to the second direction than the position on the inner surface of the downstream side first flow path on the third direction side. The liquid injection head according to claim 6, wherein the liquid injection head is provided. The liquid injection head according to any one of claims 1 to 8, and a mechanism for supplying the liquid to the supply port and collecting the liquid from the discharge port to circulate the liquid. Liquid injection system.

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